You are referring to maternal filicide.
Here are some famous cases:
LA LLORONA. Some years ago, the story goes, a young hidalgo fell in love with a lowly girl, usually named María, who over a period of time bore him two or three children. She had a casita-a little house-where the young man visited and brought his friends, and in almost every way they shared a happy life together, except that their union was not blessed by the church. His parents, of course, knew nothing of the arrangement and would not have allowed him to marry beneath his station. They urged him to marry a suitable lady and give them grandchildren. Finally he gave in, and sadly he told María that he must marry another. But he would not desert her, he promised-he would still take care of her and the children and visit them as often as he could. Enraged, she drove him away, and when the wedding took place she stood veiled in her shawl at the back of the church. Once the ceremony was over she went home, and in a crazed state killed the children, threw them into a nearby body of water, and then drowned herself.
http://www.tsha.utexas.edu/handbook/online/articles/LL/lxl1.html
Susan Smith (born as Susan Leigh Vaughan), , was convicted 22.7.1995 , of murdering her sons 3-year-old Michael Daniel Smith, and 14-month-old Alexander Tyler Smith and later sentenced to life in prison.
Andrea Pia Yates (nee Kennedy) of commited the filicide of her five young children on June 20, 2001 by drowning them in their family bathtub. Formerly convicted of first degree murder in 2002 and sentenced to life in prison .
http://edition.cnn.com/SPECIALS/2001/yates/
Dr. Debora Green was a former oncologist living in Prairie Village, Kansas, married to Michael Farrar, a cardiologist. After previously trying to poison Michael using ricin, on October 24, 1995 she murdered two of her children by setting fire to the family house at 7517 Canterbury Court.
http://pitch.com/issues/2000-05-25/points.html
Boulder law enforcement officials declared that Patricia "Patsy" Ramsey her husband were "under an umbrella of suspicion" due to their possible involvement in the crime of killing their daughter. John and Patsy Ramsey spent the next ten years defending themselves against the allegations. As of 2006 no charges have ever been filed against anyone.
Rohini Maharaj (deceased) - Killed her two sons by carbon monoxide poisoning in the garage and then committed suicide.
Christina Riggs - She was sentenced to death by lethal injection for killing her two children Justin and Shelby.
Sharon Amos - A prominent member of the Peoples Temple church in Guyana (who was not present at Jonestown, but rather at Guyana headquarters in Georgetown) slit the throats of her two children and then herself after hearing the news of mass suicide from Jonestown over the ham radio.
China Arnold murdered her newborn daughter by using a microwave oven.
http://www.msnbc.msn.com/id/15937773/
